Gas turbine engines have rotating turbine blades surrounded by a shroud. Each circular array of blades on a rotating turbine disc is closely surrounded by a shroud ring, which may be a full hoop or assembled from arcuate segments. Engine efficiency is proportional to combustion temperature, so modern gas turbines use ceramics in these shroud rings and other components, since ceramics surpass metals in heat tolerance. Ceramic matrix composite (CMC) components are often used, and they must be attached to metal support structures.
A flange is a common device for attaching components together with bolts, and flanges are often satisfactory for metal components. However, CMC has relatively weak inter-laminar tensile strength, which can cause weakness at the base of a CMC flange, especially in the cyclical thermal and mechanical stresses of a gas turbine engine environment. Thus, it has been problematic to design durable mechanisms for attaching CMC components to metal structures in gas turbines.